Inhibitory Potency ofErythrina variegataProteinase Inhibitors toward Serine Proteinases in the Blood Coagulation and Fibrinolytic Systems

SummaryA series of peptide aldehydes synthetized in our institute during the last 15 years were screened to detect their inhibitory effect on blood coagulation. Simple conventional clotting assays, platelet function tests and fibrinolytic methods were used to evaluate the inhibitory potency of the compounds in complex clotting systems as well as their supposed antifibrinolytic effect in vitro. Special attention was paid to the possible interactions with blood cells and plasma proteins, and to the functional stability of the inhibitors in several tissue homogenates. D-Phe-Pro-Arg-H (GYKI-14166, RGH-2958), Boc-D-Phe-Pro-Arg-H (GYKI-14451) and D-MePhe-Pro-Arg-H (GYKI-14766) were found to be the most potent inhibitors. The peptide aldehydes via formation of reversible complexes with thrombin impede the enzyme to react with the coagulation factors, platelet membrane and vessel wall. The compounds inhibit platelet aggregation induced by thrombin specifically without changing the sensitivity of platelets to other inducers. D-Phe-Pro-Arg-H and D-MePhe-Pro-Arg-H showed no antifibrinolytic effect. D-MePhe-Pro-Arg-H and Boc-D-Phe-Pro-Arg-H proved to be stable in dry state for years and in solution at room temperature for several days. The anticoagulant activity of the compounds was declared in NIH antithrombin units.

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The Role of Serine Proteinases in the Early Phase of Blood Coagulation

Biochemical Society Transactions ◽

10.1042/bst0051241 ◽

1977 ◽

Vol 5 (5) ◽

pp. 1241-1243

Author(s):

EARL W. DAVIE ◽

KAZUO FUJIKAWA

Keyword(s):

Blood Coagulation ◽

Early Phase ◽

Serine Proteinases

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Inhibitors of Serine Proteinases from Blood Coagulation Cascade - View on Current Developments

Mini-Reviews in Medicinal Chemistry ◽

10.2174/138955712801264819 ◽

2012 ◽

Vol 12 (8) ◽

pp. 721-730 ◽

Cited By ~ 2

Author(s):

D. Danalev

Keyword(s):

Blood Coagulation ◽

Coagulation Cascade ◽

Serine Proteinases

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The synthesis of arginylfluoroalkanes, their inhibition of trypsin and blood-coagulation serine proteinases and their anticoagulant activity

Biochemical Journal ◽

10.1042/bj2650539 ◽

1990 ◽

Vol 265 (2) ◽

pp. 539-545 ◽

Cited By ~ 18

Author(s):

T Ueda ◽

C M Kam ◽

J C Powers

Keyword(s):

Blood Coagulation ◽

Human Factor ◽

Anticoagulant Activity ◽

Factor Xa ◽

Activated Partial Thromboplastin Time ◽

Serine Proteinases ◽

Bovine Thrombin ◽

Bovine Trypsin ◽

Factor Xiia ◽

Factor Xia

Seven arginylfluoroalkanes (‘arginine fluoroalkyl ketones’) were synthesized by using a modified Dakin-West procedure. The structure of benzoyl-Arg-CF2CF3 was analysed by 19F-n.m.r. spectroscopy and m.s. and the compound was shown to exist primarily as a hydrate or cyclic carbinolamine. Arginylfluoroalkanes are good inhibitors of blood-coagulation serine proteinases and were found to be slow-binding inhibitors for bovine trypsin with Ki values of 0.2-56 microM. Benzoyl-Arg-CF2CF3 was the best inhibitor for bovine thrombin and human Factor XIa, and inhibited thrombin and Factor XIa competitively with Ki values of 13 microM and 62 microM respectively. The best inhibitor for pig pancreatic kallikrein was p-toluoyl-Arg-CF3, with a Ki value of 35 microM. Benzoyl-Arg-CF3 and benzoyl-Arg-CF2CF3 inhibited human plasma kallikrein competitively, with Ki values of 50 microM. None of the seven arginylfluoroalkanes was a good inhibitor of human factor Xa or of Factor XIIa. The arginylfluoroalkanes were tested in the prothrombin time (PT) and activated partial thromboplastin time (APTT) coagulant assays. Two fluoroketones, benzoyl-Arg-CF2CF3 and 1-naphthoyl-Arg-CF3, had significant anticoagulant activity. Benzoyl-Arg-CF2CF3 was found to prolong the PT 1.8-fold at 120 microM and to prolong the APTT 2.4-fold at 90 microM, whereas 1-naphthoyl-Arg-CF3 only prolonged the APTT 1.7-fold at 100 microM.

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